A new combination treatment for heart patients could save an estimated 10,000 lives a year in the UK.
The findings come from a British study involved more than 12,000 patients who had suffered a suspected heart attack or unstable angina.
Treatment with a combination of the heart disease drug clopidogrel and aspirin dramatically reduced the risk of dying, having a further heart attack, or suffering a stroke.
The chances of one of these events happening were 20% lower than when patients were treated with aspirin alone.
Doctors involved in the trial say the results are the biggest step forward in the treatment of coronary heart disease for 20 years.
Dr Ameet Bakhai, from the Clinical Trials and Evaluations Unit at the Royal Brompton Hospital in London, commented: "We estimate that about 120,000 patients like this come into hospitals in the UK each year.
"With the therapeutic benefit we have seen you could save about 10,000 lives per year in the UK alone.
"If you extend this to Europe and the United States you are talking about hundreds of thousands of lives. It really is a magnificent breakthrough."
Results from the study, called Cure (Clopidogrel in Unstable Angina to Prevent Recurrent Ischaemic Events), appeared in the New England Journal of Medicine. The findings will also be published in a forthcoming issue of the Lancet medical journal.
A total of 750 patients at 25 centres throughout the UK took part in the trial.